/Engine/Source/Runtime/InteractiveToolsFramework/Public/ToolTargetManager.h
Looks through the currently selected components and actors and builds a target out of the first encountered element that satisfies the requirements.
virtual [UToolTarget](API\Runtime\InteractiveToolsFramework\ToolTargets\UToolTarget) * BuildFirstSelectedTargetable ( const [FToolBuilderState](API\Runtime\InteractiveToolsFramework\FToolBuilderState) & SceneState, const [FToolTargetTypeRequirements](API\Runtime\InteractiveToolsFramework\ToolTargets\FToolTargetTypeRequirements) & TargetRequirements )